Patent GB-1469821-A (GB)
Title: Apparatus for inductively hardening workpieces
IPC: C21D9/30
Filed: 1974-06-26
Abstract: 1469821 Induction heating of rotary workpieces AEG-ELOTHERM GmbH 26 June 1974 [28 June 1973] 28421/74 Heading H5H [Also in Division C7] In an induction heating device for hardening rotating workpieces, e.g. crank-shafts 7, of the type comprising a carriage 12 traversible in a direction parallel to the axis of rotation of workpieces 7 to a plurality of working locations, a transformer table 15 supporting a transformer 16 thereon and pendantly suspended by linkage 14 from a slide 13 vertically movable on the carriage 12 and an inductor 18 attached to transformer table 15 and adapted to embrace only part of a surface of the workpiece, an inductor magazine 20 containing a plurality of inductors 21 spaced in a row parallel to the axis of rotation of the workpiece 7 is mounted within the range of traverse of the carriage 12, an automatically operable coupling device 19 for attaching an inductor to the table 15 and for establishing electrical connection of the attached inductor to the transformer secondary is provided, and programmed control means is provided to control the traverse of the carriageinductor unit between its several working positions and its inductor changing position and to control the starting and stopping of the several working steps and operations. As shown, a rotary carrier shaft 4 carriers four pairs of clamping heads 5 between which four crankshafts 7 are rotatably supported. The shaft 4 is indexable to four positions so that each crankshaft, after heating may be quenched in a quench tank 2. Each inductor 18 heats each of the crank-shafts in turn and is then moved axially with carriage 12 to a new working position or to the empty space in the magazine 20. During heating, the inductor 18, which is counterbalanced rides on the surface of the crank-shaft. When the inductor is opposite the empty space in magazine 20, slide 13 is lowered, and when the inductor rests on the magazine between locating lugs 21, the coupling 19 is automatically released, the slide 13 raised, and the carriage moved opposite the required different inductor 21 in the magazine 20. The slide is then lowered to automatically couple the new inductor to the transformer. The entire operation except for loading and unloading the workpieces in carrier 4 is automatic. In Fig. 2 (not shown) the magazine is located between the track for the carriage and the quench tank. A transfer device mounted on the carriage 12 is movable transversely to the axis of rotation of the workpiece and is provided with a cross-key for engaging a corresponding slot in an inductor housing to convey it to and from the transformer table 15 which during inductor changing is automatically locked to prevent swing of the linkage 14. The positions of the inductors in the magazine are preferably axially coincident with the various working positions so that the hardening operation may be speeded up. In Fig. 4 (not shown) each inductor is slidably suspended on rails in a compartmentalized magazine, and the transformer table 15 has rails from which the working inductor is suspended. An hydraulic flap carrying rails is raised to engage and lock transformer table 15 so that the rails of a magazine compartment, the flap, and the transformer table are aligned to enable the transfer device to move an inductor to and fro between the transformer table and the magazine. In Fig. 5 (not shown) the inductor magazine is slidably mounted on carriage 12 in a direction parallel to the axis of the workpiece. The inductor magazine and transformer table 15 have rails by which the inductors are slidably suspended. An hydraulic actuator swings the transformer table transversely to lock it in predetermined axial positions to the carriage 12. The inductor magazine is slid axially until the required inductor compartment therein is opposite the transformer table. This construction enables an inductor to be changed whilst carriage 12 is traversing to a fresh working position on the crank-shaft. The heating device may be combined with a machine which automatically feeds, clamps and removes workpieces to and from the device. The quench tank would be replaced by quench sprayers in the inductors.